


No Filter Kids

by Paper_Dragon



Category: One Piece, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Age Regression/De-Aging, Attempt at Humor, Author Headcanons, Child!Bakugou, Drabble Collection, Gen, Misunderstandings, Other Additional Tags to Be Added, Out of Character, POV Alternating, Sort Of, adopted Bakugou, character crossover, if you tilt your head and squint your eyes, more than likely - Freeform
Language: English
Status: Completed
Published: 2018-01-29
Updated: 2018-02-12
Packaged: 2019-03-10 22:49:32
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,424
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13511373
Author URL: https://archiveofourown.org/users/Paper_Dragon/pseuds/Paper_Dragon
Summary: A mishap during a inter-school training exercise leads to some unfortunate consequences. Bakugou will probably kill them all once this is over but Class 1-A can't really help but to take advantage of the situation as it is now...((Bakugou gets age reversed into a toddler and the class see the more adorable side of their grumpy Lord Explosion Murder))





	1. Chapter 1

**Author's Note:**

> So been awhile since last wrote anything and this is just something small to really get back into the feel of things, there might be some errors and such through it.... Especially grammatically...
> 
> It is a personal headcanon that Bakugou was adopted by Killer at a young age after his parents abandoned him due to his quirk being dangerous. This is in no way a reflection on the parenting of Mitsuki or Masaru - his mum is an awesome character.

Contrary to popular belief it was a rare occurrence for a school to contact Killer about his young brother, and besides the occasional comment about language during parent teacher interviews Bakugou was a rather productive student. So being called by the U.A. during the middle of work was rather surprising, especially with them refusing to provide any details as to why Killer had to essentially drop everything and book it to the academy. That was a little concerning. 

Following behind the thickly wrapped teacher, Baku had been rather negligent in actually telling him about his teachers, he couldn't help but glance at the shorter old woman walking with them. He guessed she was part of the nursing staff for the school, or perhaps science department - if there was one.  
She had shuffled her way out to walk with them moments ago but was yet to speak, seemingly busy chewing on something, and the solemn teacher had hardly spoken a word upon his arrival instead just demanding he follow him and walking off.  
"Mr Bakugou, we are terribly sorry to call you in like this." Jumping slightly at the rather sudden sweet voice coming from round his knees he tried to play the motion off as an unconcerned shrug, knowing it would be pointless to even attempt to point out Bakugou wasn't his name. It would probably look bad if he was attending an emergency situation for his brother and to suddenly start pointing out they didn't actually share a last name. He was technically his legal guardian slash parental figure, unofficially they preferred to refer to each other as brothers. 

"It's not a problem, but please what is going on? When they called no one would explain what exactly the situation was, only that it was urgent." Grip tightening within the confines of his jacket pocket he tried to resist fidgeting with his hair in nervousness as the shared look of regret that crossed both administrators faces. If the news was really so bad he'd rather have it stated to him clearly then end up being left in shock from a surprise.  
"There was an incident..." The sweet nurse hummed quietly, perhaps trying to find the right words to say what needed to be said. Only succeeding in adding unnecessary tension to his already fraying nerves, a sickening pit in his stomach wanting to drag him to the ground. 

"Stupid teenagers, no clue how to control their quirks... Irresponsible." 

Frowning at the judgemental words Killer resisted the urge to point out that they were all learning, an experienced teacher had no right to judge them so harshly. This was one of the toughest academies in the country, that produced some of the world's top heroes, their expectations were probably much greater than what he considered to be standard. In a world where heroes faced death head on, a strict high school conditioning was probably more than necessary. Still it didn't mean he personally agreed with it. 

But instead of commenting the acknowledgment of a quirk being at fault for his call out sent the unease within him writhing. Could Bakugou have done something to hurt another student? Or was he himself harmed?

"It was a simple accident. Everyone is more than alright." A withering look shot over the grey scarf, the commentary not seeming all that much appreciated. Killer certainly didn't feel any better for it.  
Rounding the corner, instead of another overly long bland hallway, a crowd was gathered round the cracked far door. As if watching someone trying to catch a loose animal, too curious to retreat fully to safety but also not willing to face it themselves. The hulking form of a second teacher noticing their approach and breaking away from the huddle of students. The bright man feeling vaguely familiar but Kill supposed they'd had a brief encounter sometime around the school over the last few months but no formal introduction. 

"Mr Bakugou it is excellent you have arrived! Young Midoriya is just making an attempt to calm the situation! No harm has come to the young Bakugou do not fear!" Why was everyone so insistent on calming his fears? He didn't even understand what he was meant to be upset about.

"Could so---"

"KILLER!!!"  
A loud shriek broke from the room as a teary eyed green haired young man basically flung himself out into the crowd, a distinct childish wailing following the abrupt departure. Seemingly setting the gathered teenagers into a flight response to escape the distraught noise. All of them slowly creeping closer to the approaching teachers seeking protection from adults in a situation that was out of their depth. 

"It's no good... None of us can get close.... he just keeps screaming murderer at everyone." Midoriya reported to the group, settling down now that he had escaped whatever was in the room. Worried looks passing round the students as another idea failed and their solutions ran thin. 

Tugging at the thick fringe over his eyes Killer tried to hold back a sigh, it didn't take a genius to figure out what was going on here. No wonder no one had been particularly keen to explain to him the situation in full, it was doubtful parents would react to the news enthusiastically in most situations. Quirks certainly did make things interesting, a little too interesting for his tastes sometimes.  
Rolling his shoulders with a slightly over exaggerated sigh he waved away the concerned expression of the teacher, easily being allowed through the collection of students to reach the rather oversized classroom door. No one seeming to want to come close to the classroom but all anxious enough to seek to stop him. Ridiculousness. Crossing the threshold he was only mildly surprised to find the room still intact, the screaming still going coming from the front, behind the solid form of the teacher lectern. 

Crouching down at angle with it so he was visible from the other side, Killer couldn't help but smile just a little over how cute Bakugou was. And the silliness of the class he'd been placed in. 

"Katsu," voice soft he reached out his arms in invitation; "it's alright now Katsu." 

Chubby hand curling round the pale wood a foggy tear filled crimson eye peaked out next, the wailing having broken off into tiny hiccups at the soft call of his name. The new quiet letting the conspiratorial whispers from the door float over to him, surprise filling the students at the lack of screaming though really it shouldn't of been that shocking.

"Killer!!" The collective gasp of fear had him breaking out into quiet chuckles, the cry not being one of distress as it had earlier but one of childish glee. Stepping forward he scooped up the chubby bundle, little hands fisting his shirt with snot and saliva from their teary adventure as a bubbling giggle left the tiny form. "Kill! Kill! Kill!" 

"Hello Katsu." He chuckled, pulling out the handkerchief from his bag to clean up the toddler, not particularly keen on having the dribble wiped all over his work shirt.... Or rubbed through his hair. The instant pale little fingers were clean they wormed their way into the thick locks, one content tangled into his hair while the other clung to his lapel. Big bright eyes completely focused on him like he was some kind of the centre of the universe.

Content Baku was clean from the hysterics of finding himself surrounded by the strangers of his class, he turned his attention directly on those people with a stern glare. A few of the students at least having the decency to look guilty under the firm gaze, a few still seemed amazed that the child had stopped crying like Killer had performed some sort of magic trick. 

"Age reversal is hardly the worst that could of happened in this situation, simply being told the instant it had happened would of saved us all a lot of stress. Especially for Katsuki." Reprimanding trained professional teachers was hardly how he wanted to spend his time, and it certainly didn't give him any sort of sway when a little hand patted his cheek like it was trying to soothe his irritation over the situation.

"We apologise Mr Bakugou, at first the situation seemed to be under control until the young Bakugou was returned to the classroom. He simply refused to be calmed and called anyone who got close a killer." At the sound of his name Baku made a gurgling giggle, bouncing in place as he reached up to tug at his fringe. Head tilted to the side he gave his best withering patiences look at the hero teacher. 

"Killer! Killer!" Baku chanted clinging to him tighter with all the might his tiny body could muster, the steady arm holding him to his hip keeping the wiggling child from climbing any higher and ending up falling. 

A look of understanding passing through at least most of the class as realisation finally came. "Bakugou did not mean the threat of a murderer then but rather the person. An unfortunate misunderstanding due to rather abnormal naming practices." Some girl stated from the back of the group, seemingly proud of herself for figuring it out, not that it seemed all that complicated to him. Then again he lived with the name for twenty-five years, things do tend to lose their strangeness at that point.

"I'm sure your parents have stories about you refusing to be handed over to strangers or left without their company when you were two." He pointed out, giving the baby a gentle bounce to try and get him to release the grip on his hair. Though it just ended up with more giggling, this was turning less into an instructive conversation the more Baku decided to get involved. Apparently he was done with Killer trying to be a serious adult figure. "Katsu..."

"F'oof gabbaa aahhii mo... Smoop!! Smoop!!" Using the grip he had on the long fringe he gave a sharp tug forward, babbling away as he positioned the other how he wanted. Keeping on eye on what the child was doing, Killer kept the other on the class, apparently childish antics were not something anyone was expecting and seeming to enjoy watching his minor struggle against the toddler.  
Though at the demand for 'smoops' he gave up, grinning brightly as somehow slightly sticky kisses were pressed to his cheek. The grin marking the success of the 'smoop' adorable on the slightly rounded cheeks. 

"Oh you want some smooches Katsu, hmm, you want smooches?" The question was met with a tiny bounce and his nose being headbutted by the excited toddler but it barely hurt enough for him to stop grinning. Leaning in he made over-exaggerated kissing noises on the soft little cheeks, nose brushing through the seemingly invisible blonde locks as the little head buried itself into his shoulder. Killer would make sure to send a sternly written letter to the school about making parents worry, it would probably be ignored, but with an armful of innocent happiness he couldn't really find it in himself to continue his triad on proper emergency call outs.


	2. Chapter 2

One eye watching the curious lean Bakugou had decided to undergo Killer tried to talk reasonably with the teacher, apparently the younger was attempting to go on an adventure but was refusing to be put down. Not really that strange, he'd always hated being on the ground, much preferring to be up where he could see things at the same level as Killer. Only a slight inconvenience. 

This particular adventure seemed to involve reaching as far as his tiny body could stretch so that the round ends of his fingers barely brushed the flame red hair of one of his classmates. The person distracted in a rather loud conversation with some friends so he paid no mind to the tickle at the back of his head. 

Curious to see what Baku would do as he rarely was interested in meeting other people, usually choosing to stick as close to Killer's side as possible, he subtly took a step forward. Having found the distance of stretch lessened Baku gave a triumphant squeak and buried his tiny fingers into the short spikes. The poor victim of his interest giving a startled shout as he whipped round to find an upside down giggling gremlin with two fists clutched round a few pulled red strands. 

Baku practically lighting up as the person of interest gave him his full attention, little fists waving as he babbled a string of childish sound. Killer having to tuck his chin into his shoulder to keep from snorting with laughter as the confused teenager rubbed the abused back of his head, giving a tiny wave at his old classmate.  
"Sorry." Swallowing the laughter but not the upward quirk of his lip betraying his grin, he shifted Baku upright, the little body instantly twisting as one hand clutched tightly to his shoulder and the other reached out for the young man. "He seems to of taken an interest in you. Would you like to say hi Katsu?"

Shuffling a little on his feet the young man smiled softly, head ducking a little as a slight pink tinged his cheeks. Maybe a little surprised by the attention. "Hi Bakugou.... Um... I'm Kirish--"

"Kiima." Baku pouted, chubby cheeks puffing up as he decided he didn't like the fact the other was ignoring his still reaching hand. A look of shocked surprise crossing the others face, moving as if on autopilot so that he was within reach of the flailing palm. Offering up his own hand to see if that was what the baby delinquent was seeking to get a hold of. 

Content to have what he was trying to get in reach he released his monkey grip on his guardian and stretched out until both hands were completely engulfed by the red strands of hair. "Ahh. Kiima!" Grinning brightly enough that his little eyes squinted closed the small hands flexed in the spiky hair, happily patting away at it as the owner stood stock still.

The shock fading Kiri couldn't help the blinding smile he shot back at the pleased baby, it was hard to be anything but over joyed with the sweet attention. Though one thing did have to be addressed. "I'm Kirishima Baku. Ki-ri-shi-ma."

Crimson eyes blinked open, a very serious expression crossing the face which tugged a tiny crinkle into the forehead that Kiri just wanted to give a gentle poke. "Kiima." Came the just as serious response, a little hand coming down to take hold of his nose. It was kind of amusing how even as a baby there was the same distinct Baku-ness that emanated from him. "Kiima."

"Come on man, Kirishima."

"Kiima."

".... Alright fine... How about you call me Eijirou? Hey, you can use my first name." 

"..... Eirou?" Pressing his lips together Kiri tried not to laugh, the soft questioning mispronunciation sounding too similar to a dog asking hello he couldn't help it.  
"Eijirou.... Ei-ji-rou?" Was 'ji' a comfortable sound for a baby, he didn't even know what was comfortable for pronunciation for someone this young. 

"Eiji!" Came the excited shriek making him jump, it wasn't perfect but that was definitely a cute nickname. He couldn't find it in himself to correct him now, it was simply accepted. That was his name now gifted from Baku. A slight tug to one of his spikes brought him closer to the child, a little hand patting his cheek comforting like he was proud he'd behaved before pointing to his own chest. "Atsu-i."  
The little frown of concentration returned like he wasn't satisfied with the word, lips silently saying it out like he was pronouncing it again and listening to the difference in sound. Before he twisted round and gave the tall man holding him a rapid pat on the cheek, whining noise leaving him to get the attention of the adult. Kiri couldn't help but notice the similarities between the two when they were this close, he hadn't even known Baku had any relations, he'd assumed of course but he tended not to talk about them. It was rather a nice surprise to be meeting his dad, even if the circumstances were kind of strange. 

"Atsu!" 

"He wants you to call him Katsuki." The soft blonde explained, blue eyes giving the same crinkling smile that Baku's did when he was absolutely content and happy, it was like seeing the opposite of the hyper aggressive teenager in an older body. It was kind of surprising how someone so nice could produce someone so intent on foul language. 

"Oh... Okay.... um hey there Katsuki." Gathering himself he turned back to the tiny child, who at the mention of their name seemed to become a wriggling ball of energy, the firm arm around his middle the only thing stopping him from falling and hurting himself as he reached out and latched onto Kiri's uniform. 

"Eiji!" Rushing to step forward to lessen the reach or risk hurting the child he was shocked by the far too Baku-ish smug expression that was shot in his direction as the toddler settled back into the grip of his father, hands clinging to the fabric of his uniform to keep him where he was wanted. A soft pap to his cheek accompanied by the quiet rumble of deep laughter had him feeling like he'd probably come to regret following the demands of the baby.


	3. Chapter 3

Babies were not his strong point. An addendum, children were not his strong point. Someone who likes the presence of children wouldn't have the highest expulsion rate in a prestigious school. Although that had less to do with personal preference and more with professional education, he could tell those that wouldn't make it as heroes against those that could, it was simply sensible to eject those that were wasting his and their time so they could realise this. 

So being handed a toddler with a cheery smile and told by his parental figure that they were going to just go grab a few necessary items and if he didn’t mind watching over the squirming ball of flesh and limbs for just a little while. Not that he really had much of a way to get out a reply seeing as the parent was already gone. Aizawa couldn’t even hand the thing off to All Might seeing as he had deemed the excursion to the store a necessary hero quest and gone with. 

That left him standing in the hallway with an armful of….!  
A small hand covering his eye cut off the mental rant, mouth thinning in a show of distaste over the action. “Zwa.” 

“…You are not going to win anything from me by attempting to play cute. Your charms do not work on me Bakugou.” He could of sworn that he was being scowled at by the child, the hand over his eye giving a threatening press as if to show that the toddler had more power than he was giving it credit for. Pulling back to free his face from grasping, poking fingers - he even took the precautionary action of lowering the little hands so they could be trapped against his chest, instead of attempting to play with his eyelids. The young boy seeming satisfied to wiggle his hands from their imprisonment to cling to his capture bands, red eyes focusing ahead once he began walking. If he had to deal with babysitting he was going to do it in the privacy of the teacher’s lounge.

This was not to escape judgement of Present Mic. 

That he was currently scheduled to teach the students English meant nothing. It certainly why it wasn’t why he was walking faster, nor checking round corners as he made his way to the supposedly empty lounge. All staff had been assigned classes for the middle lessons after this mornings departure from standard procedure, so hopefully that would mean no one would gain any blackmail material. If it spread around the school that he was actively caring for a small human like this he’d never live it down, it was already going to be a nightmare trying to keep All Might’s trap shut. 

Using his free hand and shoulder to push open the door he nearly fell backwards into the room as Bakugou chose that moment to cease using his spine. Forcing him to stumble as he caught the toddler to keep his head from bashing into the doorframe or slipping entirely from his arms, momentum carrying him backwards until his hip thunked against the desk. 

“Fu—-un.” Gritting his teeth he held back the potential swear, lowering himself slowly to sit on the desk edge that had just brought him harm. Needing a moment to just breath through the sharp sting, why was it that he could be fine being nearly crushed to death by a villain but a little table bump and it felt like the worst pain in the universe.   
Maybe the pain was amplified because of the maniacal cackle coming from the child, blonde head thrown back to an open mouthed free spirited laugh. It was slightly disturbing to see how much joy the child was taking in his pain. But also something very completely Bakugou, like of course watching a teacher panic and then cause mild injury was hilarious for him regardless of being a teenager or a young child. 

“At least you seem to be enjoying yourself.” Aizawa grunted, shifting the boy higher in his arms and successfully silencing the laughter, the little imp still grinning away and he couldn’t shake the daunting suspicion that the action had been intentional. “We’re done walking around just so you know.”   
Almost done at least, and it was a very short walk anyway, just round to grab the bag of marking he’d been holding on to for lunch and then to the couch. Hopefully in the quiet the child would sleep because there was no way Aizawa was going to play baby games with it. 

Except the usual task of simply reading through homework and grading became a struggle once the child realised there was something to do other than see how much tiny hands could squish Aizawa’s face up. Every piece of paper had to be strictly monitored or else a corner would end up crushed, torn or drooled on. Apparently paper made for an excellent chew toy. 

“Bakugou will you cease this reckless destruction I’m trying to work.” He griped, moving the child back into the small nest of cushions he had originally hoped would hold him. His finger taken hostage to be squeezed to death in a tiny grip, payment for getting too close to the restless child.   
“Zwa!”   
“I get it alright, you’re bored and wanting to be entertained. I’ve got work to do, this is your homework I’m trying to mark right now.” 

Bodily moving Bakugou back out of reach of the papers he took the precaution of shifting all the completed work back into the suitcase, it wouldn’t take him long to finish the others and he’d have at least one eye on the troublemaker. Those crimson eyes locked on target like he was merely waiting to make his move, it was surprising how committed the child was to causing mischief, or at least inconveniencing him. How well behaved he’d been under the watch of his parent it was like a switch was flipped. 

That vigilance was seeming unnecessary as Bakugou simply sat and watched, though the feeling like it was a cat teasingly watching a gecko thinking it was hidden in stillness. The marking was almost complete, safely tucked away, only a single sheet remained and he could cease worrying about grabbing hands. 

Doing a scan of his assessment of Kaminari’s poor attempt at the questions, it was certainly an improvement on the last homework he’d handed in but that still did not mean it was fantastic by any standard, hopefully the boy would continue improving. The crunch of paper broke his thought, head snapping in the direction of his charge.

“Bakgou!” There the child sat having moved in the moment he was distracted to grab what was left of the homework and crush the sheets. Mixing squeezing them between his fists, tearing at it with small nails and chewing at it with undeveloped teeth. Trying to reach for it only had the child giggling shrilly while making a wiggling dash for the limit of the couch, his previous pillow construction blocking his way enough to shorten his reach. 

“Zwa gumpee?” Scowling at the crumpled paper waving just beyond his reach he wanted to snap at the child, of course he was grumpy how was he going to explain to anyone in the class that a baby had ruined their homework.  
Then again….

Dark ringed eyes narrowing at the piece of paper he couldn’t help the way his lip quirked into a vicious smirk. The name of the student still perfectly clear on that near destroyed paper. “No Bakugou, I’m not angry at you… Why don’t you finish off that foe and we’ll have something to eat?” 

A beaming grin broke on the pudgy face, crimson eyes squinting ever so slightly as the cheeks dusted pink with pride. Mad cackle leaving him as those destructive hands tore the paper into chunky confetti, tossing it behind himself to fall between the couch arm and immovable filing cabinet, lost to all but the most diligent of spring cleans. Destruction complete Bakugou crawled over the pillow fortress and straight into Aizawa’s lap, the annoyance over the demanded attention seeming to of completely evaporated from the elder, even a small smile tugged at the usually scowling mouth. 

“This will be our little secret alright Bakugou? Don’t go telling anyone about this.”   
“Mh!”   
Banana yellow sleeping bag wrapped around them like a burrito, Aizawa fished two fruity nutrient pouch from his supply in the utility belt round his waist. With their secret pact in accord he handed the toddler the open juice, both of them leaning back like a slanted pair of dominos as they enjoyed the afternoon treat. Perhaps he might offer his services to watch over the troublesome brat again if they were needed, Bakugou wasn’t so bad like this - even if it meant having to share his sleeping bag.

…Mineta received the lowest mark the next day during homeroom; apparently his homework couldn’t be found.


End file.
